We will continue to use mouse myeloma mutants and myeloma x spleen hybridomas to study the mechanisms responsible for the synthesis and function of mouse immunoglobulins. Antigen binding mutants will be studied to determine if antibody diversity can be generated in somatic cells and to examine the relationship between antigen binding, idiotype, and sequence. Constant region mutants will be used to study the biological function of the different subclasses. Assembly and secretion will be studied using both variable region and constant region mutants. Finally, antibody forming hybridomas which can be stimulated to differentiate or be suppressed will be sought and studied.